TABLE 5.5 - Particle Density [ Station | | No. of Particles Investige ted 7 Average Density TE a 250.04 32 | 250.17 29 240 | 250.24 18 2.45 565 | (g/eu em) | (rer cent) | i Standard Deviation - | 7h | 74 ! GROSS FHYSICAL CHARACTERISTICS OF FALLOUT Comprehensive data on vhysical and chemical characteristics of fallout are preserited in the Project 2.6a renort.18/ 5 5el Surface Lard Shots It is well established that the fallout from the island shots was very similar to that which occurred after Mike shot at IVY, namely dry, white, opaque, irrerularly shaped particles. Figure 5.10 shows Shot 1 fallout as it arrived on the gummed paper collector loceted at station 250.04. It is typical of fallout from islernd detonations in the Pacific Proving Ground, 50562 Surface Water Shots Positive evidence of particulate fallout was found in the dif- — ferential collector iccated at Alice Island after Shot 6. However, the gummed paper collectors located on the free floating buoys after Shot 2 showed no evidence cf ary particles visible to the naked eye. It is felt ty come observers that the fallout. from the surface weter detona- tions was primarily in the form of a mist or aerosol. This is substantiated to some degree by the observetion of the identificetion flags located on the sea stations after Shot 2, These flags were hiphly radioactive, many times more active than the total collectors of the sane station. It, is reasonable to asswn- that a moist fine fallout would te absorred by the flapping flags much more easily than would a dry particulate, 5.6 , ‘TIME OF ARRIVAL OF FALLCUT The primary instrument for determining the period over which fell- out took plece was the differential fallcut collector, Information on time of arrival wes also obtained from the ganrma time-intensity recorder stationed on How Islend; further information may he obtained from timeintensity recorders operated by Project 2.2. Also, limited evidence of arrival tine is availaLle from the Task Force Ship's logs and Project 6.4. o7